1. Field of the Invention
This invention relates to water-activated powder compositions for improved hair bleaching.
2. Description of the Prior Art
It is well known to use hydrogen peroxide as a bleaching agent on hair. However, the use of hydrogen peroxide has the disadvantage that it does not penetrate the hair follicle. In addition hydrogen peroxide has the disadvantage of irritating sensitive scalps.
Activating compounds have been added to hydrogen peroxide for improving the penetration of bleach into the hair follicle. These liquid compositions have disadvantages such as poor shelf life and expensive shipping characteristics.
A conventional solution for eliminating the need for hydrogen peroxide is to use a dry composition which produces hydrogen peroxide when water activated. U.S. Pat. No. 4,313,932 describes a composition which forms a hair bleaching solution when mixed with water. A hydrogen peroxide producer compound is used which releases or generates hydrogen peroxide when dissolved in water and is a solid when dry. An ammonium compound in addition to a bleach accelerator is used which generates ammonium ions when dissolved in water. A thickener of finely divided silica and dried acrylic polymer latex or a homo- or copolymer of acrylamide produces desired viscosity of the solution. A bleach accelerator selected from alkali metal and either ammonium peroxydisulfates or peroxydiphosphates acts as a booster for the bleaching action. The 4,313,932 patent has the disadvantage that the use of an alkali metal accelerator may cause damage to the hair and that the use of an additional ammonium compound increases ammonia odor.
U.S. Pat. No. 4,247,537 describes a bleaching powder in a vapor proof enclosure which is capable upon aqueous activation of bleaching hair or keratinous fiber. The bleaching composition includes at least 25% by weight of ammonium persulfate, at least 25% by weight of sodium percarbonate or potassium percarbonate and at least 4 to 10% of pyrogenic silica. A two step mixing process is used for premixing the ammonium persulfate with a portion of pyrogenic silica and mixing the percarbonate compound with the remaining portion of pyrogenic silica prior to the whole composition being mixed together. The composition of this patent using at least 25% sodium percarbonate has the disadvantage that the hair may lose its normal resilience and the hair may become dry and brittle. In addition the use of at least 25% of ammonium persulfate releases an undesirable ammonia odor. Also, the use of at least 4% pyrogenic silica increases the likelihood that the bleach will dry on the head and flake off onto the face or into the eyes.
Of possible general relevance are U.S. Pat. No. 3,726,967 related to a dry free flowing bleaching composition and U.S. Pat. No. 5,064,441 relate to a solid stabilized hydrogen peroxide composition.
Common complaints by salon owners and operators are of undesirable high levels of ammonia odors and damage to the hair. A stable water-activated powder composition which prevents damage to the hair during bleaching and provides limited ammonia odor during use is desirable in the cosmetic industry.